NASSCO’s Pipeline
Assessment and Certification
Program (PACP) Overview
Rod Thornhill, PE
White Rock Consultants
Dallas, Texas
MWEA Collections Seminar
October 1, 2009
Introduction to NASSCO
Founded in 1976, NASSCO is the National Association of Sewer Service Companies.
Our mission is to set industry standards for the rehabilitation of underground pipelines and to assure the continued acceptance and growth of trenchless technologies.
NASSCO is an impartial organization serving all facets of the sewer service industry.
Step 1:Understanding Deterioration Mechanisms
Educate the Industry on how to identify problems in their sewer infrastructure system with a common defect identification program – PACP, MACP, LACP.
Define sewer pipeline deterioration modes that are common to systems containing similar materials but in different locations and climate conditions.
Assist Engineers and Municipalties on setting renewal priorites based on the documented condition of the sewer system.
Step 2:Understanding Available Technologies
Continually educating the industry on the existing and developing technolgies that can be used to renew the sewer infrastructure
Provide the tools for selecting the correct renewal technology for the sewer pipeline documented conditions
Working with the Trenchless Technology Center (TTC) of Louisiana Tech University to develop a computerized Trenchless Assessment Guide for Rehabilitation (TAG-R). This guide will give the industry the tool to quickly and effectively determine correct technology applications based on the existing condition of the pipeline
Step 3:Understanding Specifications
Write standard performance-based specifications that are made available to the Industry
Include quality assurance and quality control standards that promote quality product installation/application/construction
Provide standards for testing of the installed products to verify that the customer receives the product purchased
Step 4:Inspector Training
Certify and train project engineers and field inspectors to better understand each technology and how the technology is constructed in the field
Understanding key elements of the contract specifications to ensure successful installations
Define quality assurance requirements
Provide standard checklists and forms for accurate field documentation
0
20000
40000
60000
80000
100000
120000
140000
1880 1900 1920 1940 1960 1980
Mil
es o
f P
ipe
History of Sewer Pipe Installation
EPA Gap Analysis
0
10
20
30
40
50
60
70
80
90
100
1910 1930 1950 1970 1990 2010 2030 2050
Average Age of Sewer PipesA
ge
in
Ye
ars
EPA Gap Analysis
3
5
69 19
5
FailurePoor/Very PoorFairGoodExcellent
Estimated Condition
of Sewer Pipes In 1980
EPA Gap Analysis
12
3333
11
9
FailurePoor/Very PoorFairGoodExcellent
Estimated Condition
of Sewer Pipes In 2020
EPA Gap Analysis
0
10
20
30
40
50
60
70
80
90
100
Failed Poor/Very
Poor
Fair Good Excellent
1980
2000
2020
Estimated Change in Pipe ConditionP
erc
en
t
EPA Gap Analysis
Summary Of
TV Inspection History
Only been around about 45 years
Made possible the creation of the trenchless
technology industry
Most sewers today were only televised years
after construction
Large amount of existing TV data
Need effective way to manage volume of data
Industry Parallels
Standard Methods for the Examination of Water and Wastewater (Standard Methods) standardmethods.org
Joint Publication of APHA, AWWA, WEF
Began in 1905, now in 20th, Edition, 350
separate measurements
Proactive Renovation
and Replacement using APWA Paver
programThe pavement
Management
industry has used
condition
assessment to
justify cost-
effective
proactive
renovation
Origin of Water Research
Centre (WRc)
Condition CodesUK codes initially developed late 70s, early 80s.
Adaptations for use in Australia, Canada, and elsewhere.
Prior to NASSCO codes US industry had no single standard coding system.
WRc codes were modified and widely used in North America, however no standard version was ever established
Origin of WRc
Condition Codes (Cont’d)
Applied to help correlate sewer condition and
sewer rate charges after privatization of
industry in the UK.
NASSCO obtained assistance from WRc in
2001 and first PACP class held in Jan 2002
Standardization concept more important
than the benefits of one code system
compared to another.
Reasons for CCTV Survey
Routine Operational Requirements –
Proactive inspection to identify potential
failures and for planning routine O&M and
renovation programs.
Troubleshooting – Investigation of problem
incidents to select remedial action
Compliance with Mandated Programs –
Inspection and data collection to support
programs such as C-MOM and GASB-34.
Reasons for CCTV Survey
(Cont’d)
• Acceptance Testing – Inspection of new or renewed sewers to insure that construction met specifications and to document as-built conditions.
• I/I or CIP Projects – Examples of the type projects normally conducted by specialty firms or engineering consultants.
The PACP emphasized that all TV Inspections should be
conducted thoroughly and consistently regardless of the
reason for TV
Record and Archive All Descriptive Data
Develop a Condition Rating for Each Line
Provide Follow-up Recommendations
Display Results on a Map
Establish Benchmarks To Compare With Future Inspections Of Same Line
Estimate Probability of Failure and Life Expectancy
Desired Results of
a CCTV Survey
Why Standardization of
Codes is Important
Allows for more effort to be placed on
consistency of data and utilization of data rather
than development of utility-specific or project-
specific standards
Provides the capability of benchmarking sewers
within a single utility as well as from one
geographical area of the US to another
Provides the ability to detect change due to
deterioration over time
Why Standardization
of Codes Important (Cont’d)
Provides better opportunities for integrating data from different software programs
Improves confidence in the description of pipe conditions that will provide cost savings during renewal
Creates many opportunities for continual improvement by consistently describing conditions in a standard way over time
Advances the professionalism of TV Inspection industry
Summary of NASSCO
Pipeline Assessment and Certification
Program (PACP)
Modification/Adoption of standard codes and ratings
Training and certification of operators
Standard NASSCO data format
Certification of software vendors
Defect Grading and Severity Ratings for pipelines
Protocol for Quality Control of PACP data
Now includes manhole assessments (MACP) and soon lateral assessments (LACP)
Modification/Adoption of
standard codes and ratings
Adapt UK codes to the United States market
Re-enforce maintenance related defect codes
Add codes for corrosion evaluation/assessment
Develop codes specific to rehabilitated sewers
Training and Certification of Users
Understanding of codes and interpretation of
defects
Use of codes in forms and software
Two day course with certification exam
Includes review of pipeline deterioration
mechanisms.
Approximately 9,000 Users trained and
adopted by several hundred utilities
PACP Training Explains use of
Coding
Code Value Circumferential location
Inches
Distance (feet)
Video Ref Group /
Descrip Modifier / severity
Continuous defect
S/M/L 1st 2nd
%
Joint
At / from
To
80.3 FM J 08 05
Pipe has a
combination of
longitudinal and
circumferential
cracks
Hydrogen Sulfide Attack
STAGE 1
Inverted Syphon / Force Main
Under anaerobic (septic) conditions, sulfate present in the wastewater is
converted to sulfides within the slime layer inside the pipe. Force mains
generally flow full with little aeration therefore likely points for sulfide
production. Dissolved oxygen levels must be near zero in order for sulfide
production to occur.
STAGE 2
Discharge manhole/gravity sewer
Sulfides in the wastewater are released by turbulent conditions at discharge
point into the sewer atmosphere and form hydrogen sulfide gas (H2S).The
H2S condenses on the pipe surfaces and is converted by bacteria into a weak
sulfuric acid. The sulfuric acid attacks concrete and metal surfaces.
STAGE 1
Gravity sewer
Under anaerobic (septic) conditions sulfate present in the wastewater is
converted into sulfides within the slime layer. Sewers with laminar flow
therefore little aeration are most susceptible to low dissolved oxygen
levels
STAGE 2
Turbulence releases dissolved sulfides into the sewer atmosphere in the
form of hydrogen sulfide (H2S). The H2S then condenses on sewer
surfaces in the form of sulfuric acid. The sulfuric acid attacks cement
based materials and metals.
PACP Concrete
Pipe/H2S Damage Descriptors
Roughness increased (SRI)
Aggregate visible (SAV)
Aggregate projecting (SAP)
Aggregate missing (SAM)
Reinforcement Visible (SRV)
Reinforcement Projecting (SRP)
Reinforcement Corroded (SRC)
Missing Wall (SMW)
Roots - Medium (RM)
Code Value Circumferential
location
Inches
Distance
(feet)
Video
Ref Group /
Descrip
Modifier /
severity
Continuous
defect S/M/
L 1st 2nd
%
Joint
At /
from
To
251.6 RM S 01 20 J 07 05
Used when the roots are
50% or less of the
cross-sectional area
Certification of Software Vendors
All data fields conform to NASSCO standards
Software has the ability to export and import seamlessly to NASSCO standard data format
Data exported from one certified software is identical to software from another
PACP Standard database template freely available to anyone
PACP Data Standards
Data dictionary defines:
– Field names
– Field character number and format
– Valid field data entries
Standard Database Format (ACCESS)
Provide the ability to seamlessly
combine data from various projects
PACP QA/QC Protocol
Implementation ImportantProcess for confirming the accuracy of
PACP coding
Efficient collection of PACP data requires
accurate coding (only code once)
PACP inspections are selected randomly
for checking by Expert
Score is based on percentage of correct
entries divided by total possible entries
PACP QA/QC Protocol (Cont’d)
Protocol will find gross errors or
misinterpretations by technicians very
early in the PACP coding process
Can be used by utilities, contractors, or
engineers
Relatively small sample set can control a
large number of inspections by using
random selection of inspections once
Examples of common errors can be
used to improve coding quality
Although the Missing Wall code (SMW) and the Hole code (H)
describe similar defects, missing wall is used where the concrete is
completely deteriorated, with no pipe material left.
VC pipe material
Keys to Re-Engineering
TV Data Management
Pick a standard, preferably a nationally accepted standard
Understand TV Data Management is a program, and commit to it
Process all data from all sources consistently
Think long term, big picture
PACP Essential Tool for
Estimating Remaining Life
Records in detail the current condition of pipe
Identifies deterioration factors inside the pipe that affect rate of deterioration
Benchmarking of old and new inspections is used to ground truth rates of deterioration
Long term use of standard codes provides continual improvement
PACP-based Life Expectancy estimates will constantly be “corrected” using updated TV inspection condition data.
Utilities need to Establish
Level of Service Objectives
Traditional Levels of Service are
– Occurrence of overflows
– Frequency of maintenance calls
Emerging Levels of Service are;
– Current condition of pipeline
– Life expectancy of pipe
– Probability of Failure
Don’t Ignore Retrofitting
Existing DataVery inexpensive compared to obtaining new
data
Audio and Video often of excellent quality
Can add up quickly to a considerable portion of
the system
Provides immediate ability to assess rate of
deterioration by comparing “old” data to “new”
Summary
Standardization will increase confidence in data and
the use of the data
Develop condition ratings and recommended follow-
up for every line televised
Make mapping of results an integral part of the
process
Don’t ignore value of the existing TV data
Standardized pipe condition data will be an essential
tool for short term and longer sewer collection
system management
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